Club G40 Forum

Club G40 => General Car Chat => Topic started by: jules on July 22, 2009, 08:15:55 PM

Title: lowest octane
Post by: jules on July 22, 2009, 08:15:55 PM
Hello everybody, does anyone know what is the lowset octane fuel the 40 s will run on
because i am moving to canada and thinking of taking the G with me ,and the highest octane fuel i can find out there is 91 ron....would it run o.k ??? any help would be grateful ???
Title: Re: lowest octane
Post by: tdh-syorks on July 22, 2009, 08:27:40 PM
the engine should run fine on 91 tho you may notice that the G doesn't have the full power that it should it may lose as much as 20bhp. you need a high octane level in order to get the most out of your G, you may consider using an addative to the 91 fuel.
Title: Re: lowest octane
Post by: Bottrill on July 22, 2009, 09:27:10 PM
Shell do a 93 ron octane in canada, its marketed in the same manner as our v-power... but it still won't be as responsive.
Title: Re: lowest octane
Post by: markh450 on July 22, 2009, 10:44:27 PM
Not sure how true this is, however I have heard a few people say that the octane rating is measured differently in the states (and thus Canada??) and is actually higher than it appears?

Title: Re: lowest octane
Post by: tdh-syorks on July 23, 2009, 08:05:49 AM
the RON scale is set as standard, over in the states their (gasoline) is a lot weaker mixture than our european unleaded 95. thats probably why it costs a lot less for fuel over there. i'd say they might be a problem if you were to import a car from the states, not a V8 or anything just a standard 2.0 car, the knock as they call it from the spark with european unleaded could cause serious engine damage if a high octane fuel was used. i even think the 1.8 turbo Golfs over there have a slightly different fuel management system. correct me if i'm wrong.
Title: Re: lowest octane
Post by: Yoof on July 23, 2009, 08:30:33 AM
All OEMs now have American calibrations to suit their emissions regulations for their pump fuel- otherwise they'd not be able to market the cars over there.

If you where to import a car from the states and run it on a higher octane fuel than that it was calibrated for, you'd not have problems- they arise when the opposite is done.

Digifants knock control is prehistoric at best, so I'd not rely on this at all. You'll have to retard the ignition to avoid det. Bear in mind less advance will also give a hotter EGT so beware you don't go too mad.

Octane ratings are generally given in RON (Research Octane Number) but usually are graded in MON (Motor Octane Number) too.

What about LPG??
Title: Re: lowest octane
Post by: Andy on July 23, 2009, 12:25:06 PM
Lowest rating for a stock G40 is 95RON if memory serves, and 98RON is recommended. Whilst it'll probably run on 91RON, I don't think it'll be too happy about it - and may well det its arse off on boost.

If there's someone in Canada that can remap Digifant then that's an option - but it's probably easier just to use octane booster!
Title: Re: lowest octane
Post by: DMWG40 on July 23, 2009, 02:48:12 PM
Oliver who lived in florida I think had his G running for a long time over there. he took it with him from Germany if I remember rightly.
this was for years I knew he ran it. back in 98 to 2000 i think
Title: Re: lowest octane
Post by: hayesey on July 24, 2009, 09:57:00 AM
QuoteIf you where to import a car from the states and run it on a higher octane fuel than that it was calibrated for, you'd not have problems- they arise when the opposite is done.

yeah I agree, since octane rating is effectively a measure of resistance to knock, the lower rating the more likely you are to get det.  If you run a car designed for 91ron on 98ron then it should be perfectly ok, it wont make the same power as the same car remapped/setup for 98ron but it'll work.

But the other way round, running a car designed for at least 95ron on 91ron you are likely to get problems with detonation.  You could get the car remapped to suit, it'd make less power but it'd work.